Improve CONTRIBUTING

Noting that we don't take feature requests or 'help me' stuff on the Issues tracker should cut down a ton on bad Issues.

This reverts commit 5d95f320.

log 404 status when ActiveRecord::RecordNotFound was raised (#7646)

Rename .rb template handler to .ruby to avoid conflicts with mustache classes

Allowing pass couple extension to one register_template_handler call

Fix collection= on hm:t join models when unsaved

If assigning to a has_many :through collection against an unsaved
object using the collection=[<array_of_items>] syntax, the join models
were not properly created, previously.

Add missing entry in CHANGELOG about change of AD::Session::MemCacheStore

Remove unncessary code.

Fix build for Queue.

Fix warning: method redefine. Testcase name are duplicated.

Use synchronous queue by default. Separate queued message delivery jobs from the queued message wrappers so the queue itself needn't be marshaled (due to queue reference QueuedMessage).

improve AR/CHANGELOG [ci skip]